1. Field of the Invention
The present invention relates to mobile communications. More specifically, the present invention relates a wireless communication device that prioritizes the handling of access probes from wireless communication devices sent to a base station, preferably in a Code Division Multiple Access (CDMA) wireless communication network.
2. Description of the Related Art
In computer networks, both wired and wireless, a problem arises in “contention management,” which is when data collisions occur in a shared medium for transmission when two client machines both attempt to send data at the same time. Networking protocols include mechanisms to detect and correct for the data collisions created, such as “Carrier Sense Multiple Access With Collision Detection” (CSMA/CD), used by Ethernet, and the “Aloha” protocol for wireless networks. Aloha is an OSI layer 2 protocol for networks with broadcast topology. One major difference between Aloha and Ethernet protocols on a shared transmission medium is that Ethernet protocol uses CSMA/CD, which broadcasts a jamming signal to notify all computers connected to the channel that a collision occurred, forcing computers on the network to reject their current packet or frame. The basic Aloha protocol simply notifies the computers of the collision and requests that they send their data again later, with no specific generally accepted methodology to determine the delay.
An improvement to the original Aloha protocol was “Slotted Aloha,” which introduced discrete timeslots in which a data could be received. To implement the protocol, a centralized “clock” sends out data to the outlying clients to inform of the timing for the slots, and the clients are only allowed to send their packets immediately after receiving slot time data. A client can send only at the beginning of a timeslot, and thus collisions are reduced because the windows for a collision are greatly reduced.
Most CDMA wide-area access networks use a variant of the Slotted-Aloha protocol as an Access Channel (AC) multiple access protocol. An “access channel” is typically a mobile device-to-base station communications channel used primarily for control and sending short messages, such as call origination, page response, and registration. Individual access messages are contained in short “bursts” of data called “probes,” and the probes are handled based upon when they are received in the timing slots at the base station.
Thus, the access probes from the wireless communication device can collide within the timing slots at the base station, and the data first received in the slot will be handled to the detriment of the other devices sending colliding data. It is thus to the provision of a wireless communication device and method that prioritizes the handling of received access probes that the present invention is primarily directed.